Hydraulic mechanism



July 16, 1940- R. o. EATON 2,208,451

HYDRAULI C MECHANI SM Filed Nov. 18, 1938 Inventor: Reginald 0.Eaton,

by Wan Z6? AMA/1A1 is Attorney.

Patented July 16, 1940 2,208,451

UNITED STATESPATENT OFFICE HYDRAULIC MECHANISM Reginald 0. Eaton, Erie, Pa., assignor to General Electric Company, a corporation of New York Application November is, 1938, Serial No. 241,204 '1 Claims. (o1.'121-ss) My invention relates to hydraulic mechanism, amount of oil escapes past the packing 28 on more particularly to hydraulic motor of the pisthe lower end of the piston and collects around ton type, and has for its object means for autothe lower end of the piston in the space 29. In matically returning any fluid that leaks past the accordance with my invention, I provide a conpiston. duit passage 30 leading from the space 29 at the My invention is particularly applicable to oplowermost point of the space 29 when the piston erating'devices of the air and oil type such as is in its uppermost position through which the used for driving electric railway control .devices. leakage oil is drained through a ball-type check An operating device of this kind is disclosed in the valve 3| into a reservoir or well 32. The bottom Tritle et al. Patent No. 2,120,957, issued June 14, of this reservoir 32 is connected by a pipe 33 1938. In carrying out my invention, I provide a extending downward to the bottom of the reserreservoir for oil leaking past the piston together voir and a pipe 34 to the air chamber 20 at a with automatic pumping means operated by the point of the chamber 20 above the level of the application of air pressure to the device for forcliquid 2 ing the oil back into the oil chamber. During the operation of the device, whenever 15 For a more complete understanding of my air is admitted to the chamber 2|] it also is adinvention, reference should be had to the accommitted through the pipes 34 and 33 to the reserpanying drawing, the single figure of which is a voir 32, the check valve 3| closing to prevent view in section of a fluid operating device of application of the air pressure to the space 29.

the special type embodying my invention. When the leakage oil has collected in the reser- 20 Referring to the drawing, I have shown my voir 32 to such depth as to submerge the lower invention in one form as applied to a combined end of the pipe 33, the air entering through the air pressure and fluid operating device such as pipe 33 rises up through the oil and builds up shown in the aforesaid Tritle and McNairy patpressure in the space above the oil. When the ent. Briefly stated, the piston I0 is controlled by air pressure is released from the chamber 20 for 25 energizing or de-energizing the coils H and I2. reverse movement of the piston ID, the pressure As shown, these coils are tie-energized. The is likewise relieved in the pipes 33 and 34. The valves l4 and I5 are forced by the biasing spring entrapped air in the reservoir 32 thereupon IE to the positions shown, the valve rods being forces the oil out through the pipes 33 and 34 interlocked through a lever When the coil into the chamber 20. 30 II is energized, the valves are moved to admit I have also found that during the closing of compressed air from a suitable supply source, check valves of the ball-type 3|, a puff of air esnot shown, through the pipe 1, the valve I5 capes past the valve. In this particular applicaand pipe l9 to a pressure chamber 20 in which tion of the check valve, the ball and its seat are is a suitable liquid 2|, preferably oil. The coil I2 covered by a thin film of oil and consequently 35 controls a valve 22 which is normally biased to this puil of air picks up oil in the form of fine its closed position as shown byaspring 23. When spray and, unless means were provided to prethe valve 22 is opened by energization of the coil vent it, the oil would enter the passage 30. I2, oil is forced from the chamber 20' through To prevent that, I provide a filter 35 consisting the valve and pipe 24 to the chamber 25 under of a fine screen. An exhaust opening 36 leads 40 the piston I0. This forces the piston upward to from the upper side of the passage 30, which is 40 its upper position as shown in the drawing, When bent downward at-its end where the check valve the valve 22 is closed, the piston is held by the is placed, at a point directly above and opposite oil in its upper position. ,the check valve 3| into the interior of the filter To return the piston to its lower position, the 35. The puffs of oil spray, which are directed 45 coil I2 is energized to open the valve 22 and the substantially upward, thus escape through the coil II is de-energized whereby the valves l4 and pe 36 o t e fi ter 35. The air is free to Hi are moved to their positions shown. In this pass through the filter and escapes to the outposition the valve 4 connects the air pressure Side atmosphere through t p s 3 The pipe 13 th a pipe 26 leading t t upper end oil inthe spray, however, is removed by the filter \50 of the chamber 25 whereby air pressure is applied and u n y gravity through e C eck Valve directly to the upper 'end of the piston to force it 3| to the reservoir 32. down. The valve [5 connects the chamber :0 Provision is also made for collection of the very through the pipe IE to an air exhaust port 21. small quantity of oil which may escape through In the operation of the piston III, a small the filter screen. This oil runs down the outside 55 surface of the filter, through the threaded joint 38 by capillary attraction, and collects in the groove 39 from which it is fed back into the opening 36 through the holes 40.

Preferably the ball valve 3|eiS arranged with its seat at a slight angle with the horizontal in order to provide for free flow of the leakage oil past it into the reservoir 32. As shown in the drawing, the entire assembly containing the reservoir 32, the valve and the associated mechanism is for that purpose mounted on the housing 4| of the fluid operating device so as to be inclined at a small angle such as approximately 25 degrees with the vertical, As shown, the supporting bracket 42 is provided with an inclined face 43 to which the reservoir and mechanism is secured.

When the seat for the ball valve 3| is horizontal, the oil, I have found, tends to seal the valve against the escape of air which tends to prevent the oil from flowing through the valve into the reservoir 32. When the valve seat is inclined, the oil tends to flow through the lower side which leaves the higher side open for the escape of air. It will be understood that the operating mechanism is mounted with the cylinder 25 in a vertical position as indicated in the drawing.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto, since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claimas new and desire to secure by Letters Patent of the United States, is:

1. The combination with a liquid actuated operating device provided with a liquid chamber arranged to contain a quantity of liquid, means for admitting a compressed gas to said chamber to effect operation of said device, walls forming an enclosed reservoir for collecting liquid escaping from said device, means between said reservoir and said device preventing the flow of liquid from said reservoir to said device, and conduit means connecting a point of said chamber above the level of the liquid therein with the bottom of said reservoir whereby compressed gas from said chamber is entrapped in said reservoir and, when gas is thereafter exhausted from said chamber,

forces the liquid in said reservoir through said conduit means into said chamber.

2. An operating device comprising a cylinder, a piston in said cylinder, walls forming a liquid chamber arranged to contain a quantity of oil, conduit means connecting said chamber to said cylinder for supplying oil to said cylinder, a second conduit means for admitting compressed air to said chamber to operate said piston, walls forming an enclosed reservoir communicating;

with said cylinder for collecting oil leaking past said piston, a check valve between said reservoir and said cylinder preventing flow of fluid from said reservoir to said cylinder, a third conduit means connecting a point of said chamber above the level of the oil therein with the bottom of said reservoir so that air supplied under pressure to said reservoir fromsaid chamber is entrapped in said reservoir and, when air is thereafter exhausted from said chamber, forces the oil in said reservoir through said third conduit means into said chamber.

3. An operating device comprising a cylinder, a piston in said cylinder, walls forming a liquid chamber, conduit means connecting said chamber to said cylinder, said chamber being arranged to contain a quantity of oil filling said conduit means and said cylinder on one side of said piston, a second conduit means for admitting compreventingflow of fiuid irom said reservoir to said cylinder, a third conduit means connecting a point of said chamber above the level of the liquid therein with the bottom of said reservoir so that air supplied under pressure to said reservoir from said chamber is entrapped in said reservoir and, when air is thereafter exhausted from said chamber, forces the oil in said reservoir through said third conduit means into said chamber.

4. The combination with an oil actuated device provided with an oil chamber arranged to contain a quantity of oil, means for admitting a compressed gas to said chamber to effect operation of said device, walls forming an enclosed reservoir for collecting oil escaping from said device, conduit means connecting said reservoir and said device including valve means preventing the flow of fluid from said reservoir to said device, said conduit means being provided with a bend and an exhaust opening in said bend opposite said valve means, a second conduit means connecting a point of said chamber above the level of,

the oil therein with the bottom of said reservoir, and a filter surrounding said exhaust opening for removing oil from the air escaping through said valve means while said valve means is closing.

5. An operating device comprising a cylinder, a piston in said cylinder, walls forming a liquid chamber, conduit means connecting said chamber to said cylinder, said chamber being arranged to contain a quantity of oil filling said conduit means and said cylinder on one side of said piston, a second conduit means for admitting compressed air to said chamber to operate said piston in one direction and to said cylinder on the other side of said piston to operatesaid piston in the other direction, walls forming an enclosed reservoir, a third conduit means connecting said reservoir with said cylinder for collection of oil leaking past said piston, a check valve in said third conduit means between said reservoir and said cylinder preventing flow of liquid from said reservoir to said cylinder, said third conduit means being provided with a bend and with an exhaust opening in said bend opposite said check Valve, aiourth conduit means connecting a point of said chamber above the level of the oil therein with the bottom of said reservoir so that air supplied under pressure from said chamber to said reservoir is entrapped in said reservoir and, when air is thereafter exhausted from said chamber, forces the oil in said reservoir through said fourth conduit means into said chamber, and a filter surrounding said exhaust opening for removingoil from the air escaping through said check valve while said check valve is closing.

6. The combination with a liquid actuated device provided with a liquid chamber arranged to contain a quantity of liquid, conduit means connecting said liquid chamber to said cylinder,

means for admitting compressed air to said liquid chamber for operation of said device in one direction and for exhausting air from said chamber for movement of said device in the opposite direction, walls forming an enclosed reservoir, duct means connecting said device with the top of said reservoir for draining oil escaping from said device into said reservoir, said duct means communicating with the outside atmosphere, a check valve in said duct means preventing the escape of fluid from said reservoir, and conduit means connecting the bottom of said reservoir with said liquid chamber at a point above the level of the liquid in said chamber.

7. An operating device comprising a cylinder,.

8. piston in said cylinder, walls forming an oil chamber arranged to contain a quantity of oil, conduit means connecting said chamber to said cylinder, means for admitting compressed air to said oil chamber to move said piston in one direction and for exhausting air from said chamber for movement of said piston in the opposite di rection, walls forming an enclosed reservoir, duct means connecting said cylinder at a point above said piston with the top of said reservoir for draining oil leaking past said piston into said reservoir, said duct means communicating with the outside atmosphere, a check valve in said duct means preventing the escape of fluid from said reservoir, and conduit means connecting the bottom of said reservoir with said oil chamber at a point above the level of the oil in said chamber.

' REGINALD 0. EATON. 

